Engineering the TiO2–Graphene Interface to Enhance Photocatalytic H2 Production. Issue 2 (9th December 2013)

• Record Type: Journal Article
• Authors: Liu, Lichen; Liu, Zhe; Liu, Annai; Gu, Xianrui; Ge, Chengyan; Gao, Fei; Dong, Lin
• Is Part Of: ChemSusChem. Volume 7:Issue 2(2014:Feb.)
• Page Start: 618
• Page End: 626
• Publication Date: 2013-12-09
• Subjects: Green chemistry -- Periodicals; Sustainable engineering -- Periodicals; Chemistry -- Periodicals; Chemical engineering -- Periodicals; 660
• DOI: 10.1002/cssc.201300941
• Languages: English
• ISSNs: 1864-5631

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>In this work, TiO<sub>2</sub>–graphene nanocomposites are synthesized with tunable TiO<sub>2</sub> crystal facets ({100}, {101}, and {001} facets) through an anion‐assisted method. These three TiO<sub>2</sub>–graphene nanocomposites have similar particle sizes and surface areas; the only difference between them is the crystal facet exposed in TiO<sub>2</sub> nanocrystals. UV/Vis spectra show that band structures of TiO<sub>2</sub> nanocrystals and TiO<sub>2</sub>–graphene nanocomposites are dependent on the crystal facets. Time‐resolved photoluminescence spectra suggest that the charge‐transfer rate between {100} facets and graphene is approximately 1.4 times of that between {001} facets and graphene. Photoelectrochemical measurements also confirm that the charge‐separation efficiency between TiO<sub>2</sub> and graphene is greatly dependent on the crystal facets. X‐ray photoelectron spectroscopy reveals that TiC bonds are formed between {100} facets and graphene, while {101} facets and {001} facets are connected with graphene mainly through TiOC bonds. With TiC bonds between TiO<sub>2</sub> and graphene, TiO<sub>2</sub>‐100‐G shows the fastest charge‐transfer rate, leading to higher activity in photocatalytic H<sub>2</sub> production from methanol solution. TiO<sub>2</sub>‐101‐G with more reductive electrons and medium interfacial charge‐transfer rate also shows good H<sub>2</sub> evolution rate. As a result of its disadvantageous electronic structure and interfacial connections, TiO<sub>2</sub>‐001‐G shows the lowest H<sub>2</sub> evolution rate. These results suggest that engineering the structures of the TiO<sub>2</sub>–graphene interface can be an effective strategy to achieve excellent photocatalytic performances.</p> </abstract>